Field of the Invention
The present invention relates to a radio-frequency power supply, a radio-frequency amplifier and a method for improving an efficiency of the radio-frequency amplifier, and especially relates to a radio-frequency power supply, a radio-frequency amplifier and a method for improving an efficiency of the radio-frequency amplifier which are designed by utilizing a radio-frequency amplifier circuit design process.
Description of the Related Art
In order to respond to the requirement of the government and the environmental protection unit that the semiconductor equipment manufacturers have to reduce the carbon emission in the next few years, improving the efficiency of the power supply is an important issue. FIG. 1 shows a block diagram of the related art radio-frequency power supply. A radio-frequency power supply 100A applied to the semiconductor equipment comprises a power factor correction unit 10A, a converting unit 20A and a radio-frequency amplifier 30A. The converting unit 20A is connected between the power factor correction unit 10A and the radio-frequency amplifier 30A, and converts an alternating current input voltage Vac into an output voltage Vorf.
Please refer to FIG. 1 again. The switching frequency of the third level radio-frequency amplifier 30A is the high frequency (400 kHz-40 MHz). The biggest problem and obstacle of the efficiency of the radio-frequency power supply 100A is the switching loss of the power switch (not shown in FIG. 1) of the radio-frequency amplifier 30A when switching. Therefore, in such high switching frequency, the circuit structure that can achieve zero voltage switching to reduce the switching loss is selected. The class D and E radio-frequency amplifiers 30A are the structures which are often used. Moreover, comparing with the class D radio-frequency amplifier, the class E radio-frequency amplifier uses the single arm switch to switch. Although the cost of the switching components and driving circuit of the class E radio-frequency amplifier 30A is lower, the internal components of the circuit of the class E radio-frequency amplifier 30A are more, so that when the output power is high (about 2000 W˜3000 W), the power loss of the internal components of the circuit of the class E radio-frequency amplifier 30A and the conduction loss of the power switch is higher causing that the design of the class E radio-frequency amplifier 30A is complicated and the power application rate is low. Therefore, the class E radio-frequency amplifier 30A is still widely used in the application of the medium-low watts. The radio-frequency power supply applied to the class E radio-frequency amplifier mentioned above comprises following disadvantages:
1. The efficiency of the class E radio-frequency amplifier cannot be improved effectively. When the current class E radio-frequency amplifier is applied to the medium-high output power (about 2000 W˜3000 W) and is in the high frequency switching (400 kHz˜40 MHz), the power loss of the internal components of the class E radio-frequency amplifier is too large, so that the efficiency is low.
2. The power switch of the class E radio-frequency amplifier is selected by using the trial-and-error method. For the current method of adjusting the efficiency of the class E radio-frequency amplifier, most suitable power switches and circuit components are selected by using the trial-and-error method. First, the trial-and-error method is to maximize the cooling efficiency of the cooling system of the class E radio-frequency amplifier. After changing the power switch and the circuit components again and again, the efficiency of the class E radio-frequency amplifier is tested to adjust the efficiency of the class E radio-frequency amplifier. However, most of the highest efficiency after using the trial-and-error method is usually about only 80%.
3. There is not an effective circuit design process for the class E radio-frequency amplifier. Because the adjusting method for the current class E radio-frequency amplifier mostly is the trial-and-error method mentioned above, there is not an effective adjusting process for the circuit parameters. Therefore, adjusting the parameters of the power switch and the circuit components takes a lot of time.
Therefore, the inventors of the present invention would like to solve the problems mentioned above and design a radio-frequency power supply, a radio-frequency amplifier and its circuit design method, which are applied to the medium-high power (100˜3000 W) and are able to maintain the high efficiency.